Why don't construction prices go down?

Opportunity costs

What all is included in that for you?

All the advertising - both from private companies and politics - that WP and photovoltaics are a dream combo

But you probably didn’t believe that, did you?
But yes, it is often claimed, which is a pity, because photovoltaics can also be worthwhile on their own.
11k€ doesn’t exactly sound like a large system, how many kWP do you have?

What does your setup include?

I assume ETF fund?

11k€ doesn't exactly sound like a big system, how many kWP do you have? I guess ETF fund?

Depends. A buddy of mine had his north side of the roof and garage fully equipped with 20 kWp last year for under 10 k€.
But of course he bought the modules and substructure himself. Did all the electrical work in the house himself up to the meter and only had an Eastern European crew come for the installation on the roof. So many things are possible.

When I now see that the photovoltaic obligation will come in 2025 in many federal states, I get a little annoyed, because with today's knowledge I would at most install balcony solar and put the 11k into a random ETF.

At least before tax, an S&P 500 ETF is actually almost always better than an investment in real estate.
Although I am actually already satisfied with my electric car and photovoltaic system. But I also have a mileage of a good 20,000 km per year.

But of course he bought the modules and substructure himself. Did all the electrical work in the house himself up to the meter and only brought in an Eastern European crew for the installation on the roof. So many things are possible.

He somehow seems familiar to me - the former chancellor would have called it style.
It's probably just me.

Monthly heating costs averaged over the last 12 months: Without photovoltaic: 50.46 With photovoltaic: 46.02

But that is a very strange calculation. I keep very precise records and with my system (30kWp) this year I have a net profit after all deductions and interest (without depreciation) of around €3,750.